flat spot you'll likely feel in the wheel long before it makes a sound. whirring sounds wheel bearingy personally. CVs usually are a knocking sound that varies with load and speed. with a manual you can sometimes do good trouble shooting by pushing in the clutch and seeing if it changes while varying both engine and vehicle speed. if it changes while slowing down with the clutch pushed in and the engine idling, you know its running gear related, if it changes while vehicle speed is mostly constant and you rev the engine, then you know its engine/trans related.